1. Field of the Invention
The present invention relates to a plasma addressed electro-optical display device having its characterizing feature in the gas sealed in the plasma chamber.
2. Description of the Related Art
In the past, matrix type electro-optical devices, for example, liquid crystal display devices, using liquid crystal cells as the electro-optical cells have been known. To make these liquid crystal display devices higher in resolution and higher in contrast, active matrix type liquid crystal display devices have been developed in which thin film transistors and other switching elements are provided at each pixel and these are linearly successively driven.
In this case, however, it is necessary to provide a large number of thin film transistor like semiconductor elements on the substrate. In particular, there is the shortcoming that the manufacturing yield at the time the area is made larger becomes poorer.
Therefore, recently, a plasma addressed liquid crystal display device (PALC) where the electro-optical cells are driven using switches based on plasma discharge instead of switching elements comprised of thin film transistors etc. has been proposed (see for example Japanese Unexamined Patent Publication (Kokai) No. 1-217396, Japanese Unexamined Patent Publication (Kokai) No. 5-297359, etc.)
Such a plasma addressed liquid crystal display device has a display cell as represented by a liquid crystal display cell and a plasma cell arranged near to the same and comprised of a plasma chamber of a discharge region having plasma electrodes formed in a stripe in the columnar direction. The display cell is driven for each pixel by a virtual electrode based on the region discharged in the plasma cell and a transparent electrode arranged perpendicular to the same.
In the past, as the discharge gas sealed in such a plasma chamber, use was made of a pure gas or mixed gas comprised mainly of helium (He) or neon (Ne) gas from the viewpoint of lowering the discharge voltage (Vf).
However, in the plasma addressed liquid crystal display device of the related art explained above, the plasma decay time was long and there was the problem that it was not possible to write by a quick scan.
Further, in the above plasma addressed liquid crystal display device of the related art, the transmittance deteriorated quickly due to the sputtering of the electrode material during the discharge. Further, it suffers from the disadvantage of an abnormal discharge (ultrasmall arc discharge) along with time and a shorter panel life.
Also, in the plasma addressed liquid crystal display device of the related art, it also suffers from the disadvantage of a large discharge current (density) and the operating temperature.